Catheters with enhanced flexibility and associated devices, systems, and methods

ABSTRACT

A neuromodulation catheter includes an elongate shaft and a neuromodulation element. The shaft includes two or more first cut shapes and two or more second cut shapes along a helical path extending around a longitudinal axis of the shaft. The first cut shapes are configured to at least partially resist deformation in response to longitudinal compression and tension on the shaft and torsion on the shaft in a first circumferential direction. The second cut shapes are configured to at least partially resist deformation in response to longitudinal compression on the shaft and torsion on the shaft in both first and second opposite circumferential directions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the following applications:

-   (a) U.S. Provisional Application No. 61/717,067, filed Oct. 22,     2012; -   (b) U.S. Provisional Application No. 61/793,144, filed Mar. 15,     2013; -   (c) U.S. Provisional Application No. 61/800,195, filed Mar. 15,     2013; -   (d) U.S. Provisional Application No. 61/825,018, filed May 18, 2013; -   (e) U.S. Provisional Application No. 61/863,850, filed Aug. 8, 2013;     and -   (f) U.S. Provisional Application No. 61/863,856, filed Aug. 8, 2013.

The foregoing applications are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present technology is related to catheters. In particular, at least some embodiments are related to neuromodulation catheters having one or more cuts and/or other features that enhance flexibility, such as to facilitate intravascular delivery via transradial or other suitable percutaneous transluminal approaches.

BACKGROUND

The sympathetic nervous system (SNS) is a primarily involuntary bodily control system typically associated with stress responses. Fibers of the SNS extend through tissue in almost every organ system of the human body and can affect characteristics such as pupil diameter, gut motility, and urinary output. Such regulation can have adaptive utility in maintaining homeostasis or in preparing the body for rapid response to environmental factors. Chronic activation of the SNS, however, is a common maladaptive response that can drive the progression of many disease states. Excessive activation of the renal SNS in particular has been identified experimentally and in humans as a likely contributor to the complex pathophysiology of hypertension, states of volume overload (e.g., heart failure), and progressive renal disease.

Sympathetic nerves of the kidneys terminate in the renal blood vessels, the juxtaglomerular apparatus, and the renal tubules, among other structures. Stimulation of the renal sympathetic nerves can cause, for example, increased renin release, increased sodium reabsorption, and reduced renal blood flow. These and other neural-regulated components of renal function are considerably stimulated in disease states characterized by heightened sympathetic tone. For example, reduced renal blood flow and glomerular filtration rate as a result of renal sympathetic efferent stimulation is likely a cornerstone of the loss of renal function in cardio-renal syndrome, (i.e., renal dysfunction as a progressive complication of chronic heart failure). Pharmacologic strategies to thwart the consequences of renal sympathetic stimulation include centrally-acting sympatholytic drugs, beta blockers (e.g., to reduce renin release), angiotensin-converting enzyme inhibitors and receptor blockers (e.g., to block the action of angiotensin II and aldosterone activation consequent to renin release), and diuretics (e.g., to counter the renal sympathetic mediated sodium and water retention). These pharmacologic strategies, however, have significant limitations including limited efficacy, compliance issues, side effects, and others.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present technology can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present technology. For ease of reference, throughout this disclosure identical reference numbers may be used to identify identical or at least generally similar or analogous components or features.

FIG. 1 is a partially schematic perspective view illustrating a therapeutic system including a neuromodulation catheter configured in accordance with an embodiment of the present technology.

FIG. 2 is an enlarged partially cut-away side view of a shaft of the neuromodulation catheter shown in FIG. 1 illustrating a hypotube of the shaft and a cut extending along a helical path having varying pitch along the length of the shaft.

FIG. 3 is a two-dimensional representation of the helical path juxtaposed with a corresponding segment of the shaft shown in FIG. 2.

FIGS. 4 and 5 are two-dimensional representations of different portions of the cut shown in FIG. 2.

FIG. 6 is a partially schematic view of a neuromodulation catheter including a shaft having first and second shaft segments with different flexibilities configured in accordance with an embodiment of the present technology.

FIG. 7A is a two-dimensional representation of a helical path juxtaposed with the first shaft segment shown in FIG. 6.

FIG. 7B is an enlargement of a portion of FIG. 7A illustrating changes in slope along the helical path shown in FIG. 7A.

FIGS. 8, 9 and 10 are two-dimensional representations of different portions of a cut extending along the helical path shown in FIG. 7A.

FIGS. 11, 12A, 17, 19, 21 and 23 are two-dimensional representations of helical paths juxtaposed with corresponding shaft segments configured in accordance with several embodiments of the present technology.

FIG. 12B is an enlargement of a portion of FIG. 12A illustrating changes in slope along the helical path shown in FIG. 12A.

FIGS. 13-16 are two-dimensional representations of different portions of a cut extending along the helical path shown in FIG. 12A.

FIGS. 18, 20, 22 and 24 are two-dimensional representations of portions of cuts extending along the helical paths shown in FIGS. 17, 19, 21 and 23, respectively.

FIGS. 25-28 are two-dimensional representations of portions of cuts configured in accordance with several embodiments of the present technology.

FIGS. 29-31 are perspective views of shaft segments having guide wire exit openings with different positions relative to cuts configured in accordance with several embodiments of the present technology.

FIGS. 32 and 33 are perspective views of shaft segments including helically wound elongate members configured in accordance with several embodiments of the present technology.

FIGS. 34 and 35 are side profile views of helically wound elongate members having windings with different average helix angles configured in accordance with several embodiments of the present technology.

FIG. 36 is a side profile view of a helically wound elongate member having windings with different average helix angles on either side of a transition region configured in accordance with an embodiment of the present technology.

DETAILED DESCRIPTION

Neuromodulation catheters configured in accordance with at least some embodiments of the present technology include elongate shafts having one or more cuts and/or other features that enhance flexibility (e.g., bendability or other responsiveness to lateral force) without unduly compromising desirable axial stiffness (e.g., pushability or other responsiveness to axial force) and/or desirable torsional stiffness (e.g., torqueability or other responsiveness to torsional force). For example, a neuromodulation catheter configured in accordance with a particular embodiment of the present technology is sufficiently flexible in some respects to facilitate deployment via a relatively long and/or tortuous intravascular path without excessive resistance, while still being sufficiently stiff in other respects so as to allow intravascular navigation or other suitable manipulation via an extracorporeal handle. Desirable axial stiffness can include, for example, the capability of the shaft to be advanced or withdrawn along the length of an intravascular path without significantly buckling or elongating. Desirable torsional stiffness can include, for example, the capability of the shaft to distally transfer rotational motion (e.g., from a handle at a proximal end portion of the shaft to a neuromodulation element operably connected to the shaft via a distal end portion of the shaft) with close correspondence (e.g., at least about one-to-one correspondence). In addition or alternatively, desirable torsional stiffness can include the capability of the shaft to distally transfer rotational motion without causing whipping and/or diametrical deformation of the shaft. Desirable axial and torsional stiffness together can facilitate predictable and controlled transmission of axial and torsional force from the proximal end portion of the shaft toward the distal end portion of the shaft while a neuromodulation catheter is in use.

Metal hypodermic (needle) tubing, aka hypotubing, is commonly incorporated into small-diameter shafts of medical catheters to utilize the wire-like physical properties of such material along with the useable lumen extending therethrough. However, solid-walled metal tubing also has known limitations regarding flexibility and kink resistance, and various designs have utilized slits, slots or other openings in the tubing wall to achieve improvements in flexibility. Such modifications to the wall structure have always brought about compromises in physical properties in tension, compression, and torsion. Thus, in at least some conventional neuromodulation catheters, imparting flexibility can require unduly sacrificing axial stiffness and/or torsional stiffness. For example, creating a continuous helical cut in a relatively rigid hypotube of a shaft tends to increase the flexibility of the shaft, but, in some instances, the resulting coils between turns of the cut may also tend to separate to an undesirable degree in response to tension on the shaft and/or torsion on the shaft in at least one circumferential direction. In some cases, this separation can cause a permanent or temporary change in the length of the shaft (e.g., undesirable elongation of the shaft), a permanent or temporary diametrical deformation of the shaft (e.g., undesirable flattening of a cross-section of the shaft), and/or torsional whipping. Such shaft behavior can interfere with intravascular navigation and/or have other undesirable effects on neuromodulation procedures.

Due, at least in part, to enhanced flexibility in combination with desirable axial and torsional stiffness, neuromodulation catheters configured in accordance with at least some embodiments of the present technology can be well-suited for intravascular delivery to treatment locations (e.g., treatment locations within or otherwise proximate to a renal artery of a human patient) via transradial approaches (e.g., approaches that include the radial artery, the subclavian artery, and the descending aorta). Transradial approaches are typically more tortuous and longer than femoral approaches and at least some other commonly used approaches. Transradial approaches can be desirable for accessing certain anatomy, but other types of approaches (e.g., femoral approaches) may be desirable in particularly tortuous anatomy or vessels having relatively small diameters. In some instances, however, use of transradial approaches can provide certain advantages over use of femoral approaches. In some cases, for example, use of transradial approaches can be associated with increased patient comfort, decreased bleeding, and/or faster sealing of the percutaneous puncture site relative to use of femoral approaches.

In addition to or instead of facilitating intravascular delivery via transradial approaches, neuromodulation catheters configured in accordance with at least some embodiments of the present technology can be well suited for intravascular delivery via one or more other suitable approaches, such as other suitable approaches that are shorter or longer than transradial approaches and other suitable approaches that are less tortuous or more tortuous than transradial approaches. For example, neuromodulation catheters configured in accordance with at least some embodiments of the present technology can be well suited for intravascular delivery via brachial approaches and/or femoral approaches. Even when used with approaches that are generally shorter and/or less tortuous than transradial approaches, the combination of flexibility and desirable axial and torsional stiffness associated with neuromodulation catheters configured in accordance with at least some embodiments of the present technology can be beneficial, such as to accommodate anatomical differences between patients and/or to reduce vessel trauma during delivery, among other potential benefits.

Specific details of several embodiments of the present technology are described herein with reference to FIGS. 1-36. Although many of the embodiments are described herein with respect to devices, systems, and methods for intravascular renal neuromodulation, other applications and other embodiments in addition to those described herein are within the scope of the present technology. For example, at least some embodiments may be useful for intraluminal neuromodulation, for extravascular neuromodulation, for non-renal neuromodulation, and/or for use in therapies other than neuromodulation. It should be noted that other embodiments in addition to those disclosed herein are within the scope of the present technology. For example, in still other embodiments, the technology described herein may be used in devices, systems and methods for stent delivery and balloon angioplasty. Further, embodiments of the present technology can have different configurations, components, and/or procedures than those shown or described herein. Moreover, a person of ordinary skill in the art will understand that embodiments of the present technology can have configurations, components, and/or procedures in addition to those shown or described herein and that these and other embodiments can be without several of the configurations, components, and/or procedures shown or described herein without deviating from the present technology.

As used herein, the terms “distal” and “proximal” define a position or direction with respect to a clinician or a clinician's control device (e.g., a handle of a neuromodulation catheter). The terms, “distal” and “distally” refer to a position distant from or in a direction away from a clinician or a clinician's control device. The terms “proximal” and “proximally” refer to a position near or in a direction toward a clinician or a clinician's control device. The headings provided herein are for convenience only and should not be construed as limiting the subject matter disclosed.

Selected Examples of Neuromodulation Catheters and Related Devices

FIG. 1 is a partially schematic perspective view illustrating a therapeutic system 100 configured in accordance with an embodiment of the present technology. The system 100 can include a neuromodulation catheter 102, a console 104, and a cable 106 extending therebetween. The neuromodulation catheter 102 can include an elongate shaft 108 having a proximal end portion 108 a and a distal end portion 108 b. A handle 110 of the neuromodulation catheter 102 can be operably connected to the shaft 108 via the proximal end portion 108 a, and a neuromodulation element 112 (shown schematically) of the neuromodulation catheter 102 can be operably connected to the shaft 108 via the distal end portion 108 b. The shaft 108 can be configured to locate the neuromodulation element 112 intravascularly at a treatment location within or otherwise proximate to a body lumen (e.g., a blood vessel, a duct, an airway, or another naturally occurring lumen within the human body), and the neuromodulation element 112 can be configured to provide or support a neuromodulation treatment at the treatment location. The shaft 108 and the neuromodulation element 112 can be 2, 3, 4, 5, 6, or 7 French or one or more other suitable sizes.

In some embodiments, intravascular delivery of the neuromodulation catheter 102 includes percutaneously inserting a guide wire (not shown) into a body lumen of a patient and moving the shaft 108 and the neuromodulation element 112 along the guide wire until the neuromodulation element 112 reaches a suitable treatment location. In other embodiments, the neuromodulation catheter 102 can be a steerable or non-steerable device configured for use without a guide wire. In still other embodiments, the neuromodulation catheter 102 can be configured for delivery via a guide catheter or sheath (not shown) or in another suitable manner.

The console 104 can be configured to control, monitor, supply, and/or otherwise support operation of the neuromodulation catheter 102. Alternatively, the neuromodulation catheter 102 can be self-contained or otherwise configured for operation without connection to the console 104. When present, the console 104 can be configured to generate a selected form and/or magnitude of energy for delivery to tissue at the treatment location via the neuromodulation element 112 (e.g., via one or more energy delivery elements (not shown) of the neuromodulation element 112). The console 104 can have different configurations depending on the treatment modality of the neuromodulation catheter 102. When the neuromodulation catheter 102 is configured for electrode-based, heat-element-based, or transducer-based treatment, for example, the console 104 can include an energy generator (not shown) configured to generate radio frequency (RF) energy (e.g., monopolar and/or bipolar RF energy), pulsed energy, microwave energy, optical energy, ultrasound energy (e.g., intravascularly delivered ultrasound, extracorporeal ultrasound, and/or high-intensity focused ultrasound (HIFU)), cryotherapeutic energy, direct heat energy, chemicals (e.g., drugs and/or other agents), radiation (e g, infrared, visible, and/or gamma radiation), and/or another suitable type of energy. When the neuromodulation catheter 102 is configured for cryotherapeutic treatment, for example, the console 104 can include a refrigerant reservoir (not shown) and can be configured to supply the neuromodulation catheter 102 with refrigerant. Similarly, when the neuromodulation catheter 102 is configured for chemical-based treatment (e.g., drug infusion), the console 104 can include a chemical reservoir (not shown) and can be configured to supply the neuromodulation catheter 102 with one or more chemicals.

In some embodiments, the system 100 includes a control device 114 along the cable 106. The control device 114 can be configured to initiate, terminate, and/or adjust operation of one or more components of the neuromodulation catheter 102 directly and/or via the console 104. In other embodiments, the control device 114 can be absent or can have another suitable location (e.g., within the handle 110). The console 104 can be configured to execute an automated control algorithm 116 and/or to receive control instructions from an operator. Furthermore, the console 104 can be configured to provide feedback to an operator before, during, and/or after a treatment procedure via an evaluation/feedback algorithm 118.

FIG. 2 is an enlarged partially cut-away side view of the shaft 108 illustrating a hypotube 120 concentrically disposed within an outside wall 121. The hypotube 120 can be configured to reinforce the shaft 108 against collapsing from lateral compression. For example, the hypotube 120 can be made of a relatively strong material (e.g., nitinol, stainless steel (e.g., 304 stainless steel), or another suitable metal). The hypotube 120 may be disposed within all or a portion of the shaft 108. In some embodiments, for example, the hypotube 120 may only be disposed at a distal section of the shaft 108, and a proximal section of the shaft 108 may have a different arrangement and/or configuration. Tubes made of relatively strong materials tend to be relatively stiff (e.g., resistant to bending) when unmodified. To increase the flexibility of the neuromodulation catheter 102, the shaft 108 can include a cut 122 extending at least partially through a wall thickness of the hypotube 120, the outside wall 121, or another suitable portion of the shaft 108. For example, the shaft 108 can have a longitudinal axis 124 and the cut 122 can follow a helical path 126 that extends about the longitudinal axis 124 (e.g., a coiled, spiral, or other similar form having two or more turns consistently or variably spaced along the longitudinal axis 124). The cut 122 can be continuous or discontinuous along the helical path 126. Furthermore, the shaft 108 can be cut along more than one helical path (e.g., a double helix having two or more helical paths having the same “hand” or chirality and spaced apart along the longitudinal axis 124). The cut 122 can be formed, for example, using laser etching, electrical discharge machining, chemical etching, or other suitable techniques. In a particular embodiment, the hypotube 120 has an outer diameter of 0.813 mm (0.032 inch) and an inner diameter of 0.635 mm (0.025 inch). In other embodiments, the hypotube 120 can have other suitable dimensions.

FIG. 3 is a two-dimensional representation of the helical path 126 juxtaposed with a corresponding segment 127 of the shaft 108. In particular, FIG. 3 is a representation of the helical path 126 and the corresponding segment 127 of the shaft 108 with the x-axis in FIG. 3 corresponding to the longitudinal axis 124 of the shaft 108 and the y-axis in FIG. 3 corresponding to the circumference of the shaft 108. In other words, FIG. 3 illustrates the helical path 126 as though the segment 127 of the shaft 108 were aligned with the x-axis and rolled along the y-axis with the helical path 126 unwinding to a flat ribbon or making an imprinted image as the segment 127 of the shaft 108 is rolled. As represented in FIG. 3, the helical path 126 can include a first portion 126 a, a second portion 126 b, and a third portion 126 c (arranged distal to proximal). The first portion 126 a, the second portion 126 b, and the third portion 126 c can extend around portions of the longitudinal axis 124 corresponding to a first portion 127 a, a second portion 127 b, and a third portion 127 c of the segment 127, respectively. In some embodiments, the first portion 127 a is distal to the second and third portions 127 b, 127 c, and the second portion 127 b is between the first and third portions 127 a, 127 c. In other embodiments, the first, second, and third portions 127 a-127 c can be reversed or have another suitable arrangement. The first, second, and third portions 127 a-127 c can be directly adjacent to one another or spaced apart from one another along the longitudinal axis 124. Furthermore, the first portion 127 a can be directly adjacent to or spaced apart from a distalmost portion of the shaft 108 (e.g., a junction between the shaft 108 and the neuromodulation element 112), and the third portion 127 c can be directly adjacent to or spaced apart from a proximalmost portion of the shaft 108 (e.g., a junction between the shaft 108 and the handle 110).

As shown in FIG. 3, the first, second, and third portions 126 a-126 c of the helical path 126 can have different slopes when transposed two-dimensionally. These slopes can correspond to the axial density (e.g., frequency or pitch angle) of features (e.g., turns, shapes, types, sizes, dimensions, or other suitable features) of the cut 122 along the longitudinal axis 124. For example, the first portion 126 a can have a greater slope than the second portion 126 b, and the third portion 126 c can be curved with a slope that gradually transitions between the slopes of the first and second portions 126 a, 126 b. Accordingly, the cut 122 can have a greater axial density of features at a portion of the longitudinal axis 124 corresponding to the first portion 127 a of the segment 127 than along a portion of the longitudinal axis 124 corresponding to the third portion 127 c of the segment 127. Similarly, the axial density of features of the cut 122 along the longitudinal axis 124 can increase gradually or in another suitable manner along the second portion 127 b from the third portion 127 c toward the first portion 127 a. For example, gradually increasing or otherwise transitioning the axial density of turns, shapes, slope, type, size/dimension, or other suitable features of the cut 122 may reduce focused stress on the shaft 108, which can reduce or eliminate kinking or other undesirable behavior of the shaft 108 during movement (e.g., bending).

By varying the axial density of features of the cut 122, different segments of the shaft 108 can have different levels of flexibility. For example, with reference to FIGS. 1-3 together, a greater axial density of features can correspond to greater flexibility than a lesser axial density of features. In some cases, a distance along the longitudinal axis 124 between the neuromodulation element 112 and the segment 127 or a portion thereof (e.g., the first, second, or third portions 127 a-c) can be selected such that the segment 127 or portion thereof tends to be disposed in or near a particular anatomical location when the neuromodulation catheter 102 is in use. For example, the distance along the longitudinal axis 124 between the neuromodulation element 112 and the segment 127 or portion thereof can be selected such that the segment or portion thereof tends to be at least proximate to a relatively sharply angled or otherwise relatively tortuous anatomic region of an approach (e.g., a transradial or other suitable approach) when the neuromodulation element 112 is at a selected treatment location (e.g., a treatment location within or otherwise proximate to a renal artery of a human patient). The relatively sharply angled or otherwise relatively tortuous region, for example, can be a region within or otherwise proximate to a subclavian artery (e.g., a portion of a subclavian artery adjacent to the descending aorta), an ostium of a renal artery, or another suitable anatomical feature. The axial density of features of the cut 122 along the length of the shaft 108 and the relative flexibilities of shaft 108 along its length can be selected to facilitate transradial catheterization or deployment of the neuromodulation catheter 102 via another suitable approach. In some embodiments, an axial density of features of the cut 122 along the longitudinal axis 124 varies along the length of the shaft 108 (e.g., to tailor the shaft 108 to the tortuosity or other geometry of different portions of a transradial or other suitable approach). In other embodiments, the axial density of features of the cut 122 can be consistent along the length of the shaft 108 (e.g., to increase the overall flexibility of the shaft 108). These concepts are discussed in further detail below with reference to FIGS. 6-11.

FIG. 4 is a two-dimensional representation of a portion of the cut 122 at the first portion 126 a of the helical path 126. Such a two-dimensional representation is as if the shaft were rolled over a flat surface to leave an imprint of the cut shape therein. In some instances, this type of two-dimensional representation can be used as input for an automated manufacturing process used to form cut shapes along a path in a tubular workpiece. With reference to FIGS. 2-4 together, the shaft 108 can include two or more first cut shapes 128 and two or more second cut shapes 130 interspersed along the helical path 126, with the first and second cut shapes 128, 130 forming portions of the cut 122. The first cut shapes 128 can be configured to at least partially interlock to thereby resist deformation in response to a set of three types of force acting on the shaft 108, and the second cut shapes 130 can be configured to at least partially interlock to thereby resist deformation in response to a different, complementary set of three types of force acting on the shaft 108. The sets can be different combinations of (a) compression along the longitudinal axis 124, (b) tension along the longitudinal axis 124, (c) torsion in a first circumferential direction perpendicular to the longitudinal axis 124, and (d) torsion in a second, opposite circumferential direction perpendicular to the longitudinal axis 124. For example, the first cut shapes 128 can be configured to at least partially resist deformation in response to compression on the shaft 108, tension on the shaft 108, and torsion on the shaft 108 in the first circumferential direction, and the second cut shapes 130 can be configured to at least partially resist deformation in response to compression on the shaft 108, torsion on the shaft 108 in the first circumferential direction, and torsion on the shaft 108 in a second circumferential direction opposite to the first circumferential direction. The first cut shapes 128 can be less resistant to deformation in response to torsion on the shaft 108 in the second circumferential direction than the second cut shapes 130. Similarly, the second cut shapes 130 can be less resistant to deformation in response to tension on the shaft 108 than the first cut shapes 128. Working together, the first and second cut shapes 128, 130 can provide the shaft 108 with sufficient resistance to deformation in response to all types of axial and torsional force that may act on the shaft 108 during use of the neuromodulation catheter 102.

In some embodiments, the first and second cut shapes 128, 130 are sinusoidal and have amplitudes with different (e.g., perpendicular) orientations relative to the longitudinal axis 124. In other embodiments, the first and second cut shapes 128, 130 can have other suitable forms. For example, as shown in FIG. 4, the individual first cut shapes 128 can include a first peak 132 (e.g., a first finger) and a second peak 134 (e.g., a second finger) with a first interface 136 therebetween. The first interface 136 can be perpendicular to the longitudinal axis 124 (FIG. 2). The individual second cut shapes 130 can include a third peak 138 (e.g., a third finger) and a fourth peak 139 (e.g., a fourth finger) with a second interface 140 therebetween. The second interface 140 can be parallel to the longitudinal axis 124. Alternatively, the first and second interfaces 136, 140 can have other suitable angles relative to the longitudinal axis 124, such as other suitable angles in which an angle between the first interface 136 and the longitudinal axis 124 is greater than an angle between the second interface 140 and the longitudinal axis 124. Furthermore, in some or all of the first cut shapes 128 the orientations of the first and second peaks 132, 134 can be reversed and/or in some or all of the second cut shapes 130 the orientations of the third and fourth peaks 138, 139 can be reversed. For example, as represented in FIG. 4, the first and second peaks 132, 134 extend vertically downward and upward, respectively and the third and fourth peaks 138, 139 extend to the right and to the left, respectively. In other embodiments, the first and second peaks 132, 134 can extend vertically upward and downward, respectively and the third and fourth peaks 138, 139 can extend to the left and to the right, respectively. Other cut shapes with chirality described herein can be similarly modified. With reference again to FIG. 4, the first and second cut shapes 128, 130 can be configured to at least partially resist deformation in response to forces perpendicular to the first and second interfaces 136, 140, respectively. For example, such forces can cause the first and second peaks 132, 134 or the third and fourth peaks 138, 139 to at least partially interlock and thereby prevent or reduce widening of the cut 122.

FIG. 5 is a two-dimensional representation of a portion of the cut 122 at the second portion 126 b of the helical path 126. With reference to FIGS. 2, 3 and 5 together, an average length of the first interfaces 136, an average length of the second interfaces 140, or both can be different at different portions of the helical path 126. For example, the average length of the second interfaces 140 can be greater among the second cut shapes 130 along the third portion 126 c of the helical path 126 and the third portion 127 c of the segment 127 of the shaft 108 than among the second cut shapes 130 along the first portion 126 a of the helical path 126 and the first portion 127 a of the segment 127. In some cases, the average length of the first interfaces 136, the second interfaces 140, or both are selected based on different axial densities of features of the cut 122 at different segments of the shaft 108. For example, when the axial density is greater, the lengths of the first and second interfaces 136, 140 can be more restricted than when the axial density is lower (e.g., so as to avoid overlapping at adjacent turns).

In at least some cases, enhancing the flexibility of a shaft using a helical cut may reduce axial and torsional stiffness of the shaft to some degree even when cut shapes or features configured in accordance with embodiments of the present technology are present. Accordingly, it can be useful to include a cut along a segment of a shaft that is intended to extend through particularly tortuous anatomy, while leaving another segment of the shaft uncut or having a cut that imparts relatively little flexibility to the shaft. In this way, while the axial and torsional stiffness of the shaft may be compromised to some degree in favor of enhanced flexibility along a part of the shaft for which the enhanced flexibility is needed, the degree to which the overall axial and torsional stiffness of the shaft is compromised may be minimized or at least reduced.

FIG. 6, for example, is a partially schematic view of a neuromodulation catheter 141 including a shaft 142 having first and second shaft segments 143, 144 with different flexibilities configured in accordance with an embodiment of the present technology. The second shaft segment 144 can be proximal to the first shaft segment 143 and can be less flexible (e.g., more resistant to deflection in response to lateral force) than the first shaft segment 143. The usefulness of enhanced flexibility may tend to diminish proximally. For example, in a transradial approach, the first shaft segment 143 may need to extend through a junction between a subclavian artery and the descending aorta in order to deliver the neuromodulation element 112 to a treatment location within a renal artery of a patient. In contrast, the second shaft segment 144 may remain proximal to this junction. In some embodiments, the shaft 142 includes a cut (not shown) at the first shaft segment 143 and a different cut (not shown) at the second shaft segment 144 that imparts significantly less flexibility to the shaft 142 than the cut at the first shaft segment 143. In other embodiments, the first shaft segment 143, the second shaft segment 144, or both can be uncut. This may be the case, for example, when the relative flexibilities of the first and second shaft segments 143, 144 are influenced by factors in addition to or instead of the presence of cuts.

The location of a transition between the first and second shaft segments 143, 144 can be selected so that the second shaft segment 144 remains proximal to the subclavian artery when the shaft 142 extends along a transradial approach. In some embodiments, the first and second shaft segments 143, 144 together make up the entire length of the shaft 142 from the handle 110 to the neuromodulation element 112. In other embodiments, however, the shaft 142 may include additional segments. The first shaft segment 143 can be directly adjacent to or otherwise proximate to (e.g., within about 3 cm (1.181 inches) of) the neuromodulation element 112. The second shaft segment 144 can be directly adjacent to or otherwise proximate to (e.g., within about 3 cm (1.181 inches) of) the handle 110. In some embodiments, the first shaft segment 143 has a length from about 30 cm (11.81 inches) to about 80 cm (31.5 inches) (e.g., from about 40 cm (15.75 inches) to about 70 cm (27.56 inches)) and the second shaft segment 144 has a length greater than about 40 cm (15.75 inches) (e.g., greater than about 50 cm (19.69 inches)). In a particular embodiment, the first shaft segment 143 has a length of about 50 cm (19.69 inches) and the second shaft segment 144 has a length of about 80 cm (31.5 inches). In other embodiments, the first and second shaft segments 143, 144 can have other suitable lengths.

As discussed above with reference to FIG. 3, changing the axial density of features of a cut can change the flexibility of a shaft including the cut. With reference again to FIG. 6, the shaft 142 can include a cut having a greater axial density of features at the first shaft segment 143 than at the second shaft segment 144. For example, the axial density of features at the second shaft segment 144 can be relatively low when the second shaft segment 144 is cut in a manner that imparts relatively little flexibility to the shaft 142 or the axial density can be zero when the second shaft segment 144 is uncut. The transition from the first shaft segment 143 to the second shaft segment 144 can be gradual or abrupt. As also discussed above with reference to FIG. 3, a gradual transition in axial density may reduce focused stress and thereby reduce kinking or other undesirable behavior during movement (e.g., bending) of the shaft 142. Such gradual transitioning can include, for example, changing the axial density of features continuously or incrementally.

FIG. 7A is a two-dimensional representation of a helical path 146 juxtaposed with the first shaft segment 143 shown in FIG. 6. Similar to the helical path 126 shown in FIG. 3, the slope of the helical path 146, when transposed two-dimensionally, can correspond to an axial density of features along a longitudinal axis 145 of the shaft 142. The helical path 146 can have portions 146 a-c (arranged distal to proximal) corresponding, respectively, to portions 143 a-c of the first shaft segment 143. FIG. 7B is an enlargement of a portion of FIG. 7A illustrating changes in slope along the helical path 146. As shown in FIG. 7A, the slope of the helical path 146 can be consistent along the portion 146 a at a first value, consistent along the portion 146 b at a second, lesser value, and consistent along the portion 146 c at a third, still lesser value. The first value can be, for example, from about 15 degrees to about 40 degrees. The second value can be, for example, from about 2 degrees to about 6 degrees less than the first value. Similarly, the third value can be, for example, from about 2 degrees to about 6 degrees less than the second value. In a particular embodiment, the first value is about 40 degrees, the second value is about 36 degrees, and the third value is about 32 degrees. The length of the portion 143 a can be, for example, from about 20 cm (7.874 inches) to about 70 cm (27.56 inches) or from about 30 cm (11.81 inches) to about 60 cm (23.62 inches). The individual lengths of the portions 143 b, 143 c can be, for example, from about 2 cm (0.7874 inch) to about 7 cm (2.756 inches). In a particular embodiment, the length of the portion 143 a is 40 cm (15.75 inches) and the individual lengths of the portions are 5 cm (1.969 inches). In other embodiments, the helical path 146, the shaft 142, and portions thereof may have other suitable dimensions, such as dimensions within about 10%, 20% or 30% of the dimensions in the illustrated embodiment.

FIGS. 8, 9 and 10 are two-dimensional representations of different portions of a cut 147 extending along the helical path 146. The portions of the cut 147 shown in FIGS. 8, 9 and 10 can be positioned at the portions 146 a, 146 b, 146 c of the helical path 146, respectively. The features of the cut 147 can be similar to the features described above with reference to FIG. 5. As shown in FIG. 8, the cut 147 can have dimensions A-1, B-1, C-1, and D-1 at the portion 146 a of the helical path 146. As shown in FIG. 9, the cut 147 can have dimensions A-2, B-2, C-2, and D-2 at the portion 146 b of the helical path 146. As shown in FIG. 10, the cut 147 can have dimensions A-3, B-3, C-3, and D-3 at the portion 146 c of the helical path 146. In the illustrated embodiment, A-1 is 0.813 mm (0.032 inch); A-2 and A-3 individually are 0.09144 cm (0.036 inch); B-1, B-2 and B-3 individually are 0.02286 cm (0.009 inch); C-1 is 0.3048 cm (0.120 inch); C-2 is 0.381 cm (0.150 inch); C-3 is 0.3429 cm (0.135 inch); D-1 is 40 degrees; D-2 is 32 degrees; D-3 is 36 degrees; the radius of curvature of the cut 147 at the ends of the individual first, second, third, and fourth peaks 132, 134, 138, 139 is 0.0127 cm (0.005 inch); and the radius of curvature of the cut 147 where the first cut shapes 128 meet the helical path 146 toward an adjacent second cut shape 130 is 0.0254 cm (0.010 inch). In other embodiments, the cut 147 can have other suitable dimensions, such as dimensions within about 10%, 20% or 30% of the dimensions in the illustrated embodiment. The width of the cut 147 can be, for example, from about 0.001016 cm (0.0004 inch) to about 0.003556 cm (0.0014 inch), from about 0.001524 cm (0.0006 inch) to about 0.003048 cm (0.0012 inch), or within another suitable range.

A-1 can be less than A-2 and A-3. Similarly, the length of the second interface 140 at the portion 146 a of the helical path 146 can be less than the length of the second interface 140 at the portions 146 b, 146 c of the helical path 146. As discussed above with reference to FIG. 5, this can be useful, for example, to maintain adequate spacing between the second cut shapes 130 at adjacent turns of the cut 147 when the axial density of features is relatively high. In some embodiments, the lengths of the second interfaces 140 increase abruptly in a proximal direction along the longitudinal axis 145. In other embodiments, the lengths of the second interfaces 140 can increase gradually in a proximal direction along the longitudinal axis 145. For example, the lengths of the second interfaces 140 can increase gradually along all or a portion of the length of the first shaft segment 143. In still other embodiments, the lengths of the second interfaces 140 can remain consistent.

FIGS. 11, 12A, 17, 19, 21 and 23 are two-dimensional representations of helical paths 148, 151, 156, 162, 180, 193, respectively, juxtaposed with corresponding shaft segments 149, 153, 158, 164, 182, 194, respectively, in accordance with several embodiments of the present technology. FIG. 12B is an enlargement of a portion of FIG. 12A illustrating changes in slope along the helical path 151. FIGS. 13-16 are two-dimensional representations of different portions of a cut 154 extending along the helical path 151. FIGS. 18, 20, 22 and 24 are two-dimensional representations of portions of cuts 160, 166, 184, 195, respectively, extending along the helical paths 156, 162, 180, 193, respectively.

Relative to the helical path 126 shown in FIG. 3, the helical paths 146, 148, 151, 156, 162, 180, 193 shown in FIGS. 7A, 11, 12A, 17, 19, 21 and 23 illustrate several additional examples of transitions in axial densities of features along longitudinal axes 145 corresponding to shaft segments. In the embodiment illustrated in FIG. 7A, the slope of the helical path 146 decreases proximally in two steps. In other embodiments, the slope of a helical path can decrease proximally in more than two steps (e.g., three steps, four steps, or a greater number of steps). For example, in the embodiment illustrated in FIG. 12A, the slope of the helical path 151 decreases proximally in three steps. Similarly, in the embodiment illustrated in FIG. 17, the slope of the helical path 151 decreases proximally in seven steps. In still other embodiments, the slope of a helical path can decrease proximally in a continuous or nearly continuous manner such that all or a portion of the helical path is curved. For example, as shown in FIG. 11, rather than decreasing in steps, the slope of the helical path 148 decreases continuously in a proximal direction along the entire length of the corresponding shaft segment 149.

When a helical path decreases in steps, the locations of the steps along the longitudinal axis 145 of the corresponding shaft segment can have various suitable positions. As an example, in the embodiment illustrated in FIG. 7A, the portion 143 a of the first shaft segment 143 spans over half the length of the first shaft segment 143. The portions 143 b, 143 c of first shaft segment 143 are of equal length and together span less than a quarter of the length of the first shaft segment 143. As another example, in the embodiment illustrated in FIG. 12A, the portions 153 a-153 d of the shaft segment 153 each have different lengths along the longitudinal axis 145 of the shaft segment 153, with their lengths decreasing proximally from the portion 153 a to the portion 153 d. Similarly, in the embodiment illustrated in FIG. 19, the portions 164 a-164 c of the shaft segment 164 each have different lengths along the longitudinal axis 145 of the shaft segment 164, with their lengths decreasing proximally from the portion 164 a to the portion 164 c. Also similarly, in the embodiment illustrated in FIG. 21, the portions 182 a-182 c of the shaft segment 182 each have different lengths along the longitudinal axis 145 of the shaft segment 182, with their lengths decreasing proximally from the portion 182 a to the portion 182 c. Also similarly, in the embodiment illustrated in FIG. 23, the portions 194 a 194 c of the shaft segment 194 each have different lengths along the longitudinal axis 145 of the shaft segment 194, with their lengths decreasing proximally from the portion 194 a to the portion 194 c. As yet another example, in the embodiment illustrated in FIG. 17, the portions 158 a-158 h of the shaft segment 158 have approximately equal lengths along the longitudinal axis 145 of the shaft segment 158.

In the embodiment shown in FIG. 12A, the slopes of the helical path 151 along its portions 151 a, 151 b, 151 c, and 151 d are 36 degrees, 32.5 degrees, 27 degrees, and 23 degrees, respectively, and the lengths of the portions 153 a, 153 b, 153 c, and 153 d of the shaft segment 153 are 30 cm (11.812 inches), 9.855 cm (3.880 inches), 5.885 cm (2.317 inches), and 4.092 cm (1.611 inches), respectively. In the embodiment shown in FIG. 17, the slopes of the helical path 156 along its portions 156 a, 156 b, 156 c, 156 d, 156 e, 156 f, 156 g, and 156 h are 36 degrees, 32 degrees, 27 degrees and 23 degrees, 20 degrees, 17.7 degrees, 15.8 degrees, and 15 degrees, respectively, and the lengths of the portions 158 a, 158 b, 158 c, 158 d, 158 e, 158 f, and 158 g of the shaft segment 158 are 65 mm (2.559 inches), 62.2 mm (2.449 inches), 62.5 mm (2.461 inches), 62.5 mm (2.461 inches), 62.6 mm (2.465 inches), 62.5 mm (2.461 inches), 62.5 mm (2.461 inches), and 62.5 mm (2.461 inches), respectively. In the embodiment shown in FIG. 19, the slopes of the helical path 162 along its portions 162 a, 162 b, and 162 c are 36 degrees, 32 degrees, and 27 degrees, respectively, and the lengths of the portions 164 a, 164 b, and 164 c of the shaft segment 164 are 180 mm (7.087 inches), 174 mm (6.85 inches), and 146 mm (5.748 inches), respectively. In the embodiment shown in FIG. 21, the slopes of the helical path 180 along its portions 180 a, 180 b, and 180 c are 29.5 degrees, 27 degrees, and 24.9 degrees, respectively, and the lengths of the portions 182 a, 182 b, and 182 c of the shaft segment 182 are 179 mm (7.047 inches), 174 mm (6.85 inches), and 145 mm (5.709 inches), respectively. Similar to the embodiment shown in FIG. 21, in the embodiment shown in FIG. 23, the slopes of the helical path 193 along its portions 193 a, 193 b, and 193 c are 29.5 degrees, 27 degrees, and 24.9 degrees, respectively, and the lengths of the portions 194 a, 194 b, and 194 c of the shaft segment 194 are 179 mm (7.047 inches), 174 mm (6.85 inches), and 145 mm (5.709 inches), respectively. In other embodiments, the helical paths 151, 156, 162, 180, 193 can have other suitable dimensions, such as dimensions within about 10%, 20% or 30% of the dimensions in the illustrated embodiments.

With reference to FIGS. 12A-16, the portions of the cut 154 shown in FIGS. 13, 14, 15, and 16, respectively, can be positioned at the portions 153 a, 153 b, 153 c, and 153 d, respectively, of the shaft segment 153. The features of the cut 154 can be similar to the features described above with reference to FIGS. 5 and 8-10. For example, as shown in FIG. 13, the cut 154 can have dimensions A-4, B-4, C-4, and D-4 at the portion 151 a of the helical path 151. As shown in FIG. 14, the cut 154 can have dimensions A-5, B-5, C-5, and D-5 at the portion 151 b of the helical path 151. As shown in FIG. 15, the cut 154 can have dimensions A-6, B-6, C-6, and D-6 at the portion 151 c of the helical path 151. As shown in FIG. 16, the cut 154 can have dimensions A-7, B-7, C-7, and D-7 at the portion 151 d of the helical path 151. In the illustrated embodiment, A-4 and A-5 individually are 0.0762 cm (0.030 inch); A-6 is 0.0889 cm (0.035 inch); A-7 is 0.1143 cm (0.045 inch); B-4, B-5, B-6, and B-7 individually are 0.0381 cm (0.015 inch); C-4, C-5, and C-6 individually are 0.508 cm (0.200 inch); C-7 is 0.635 cm (0.250 inch); D-5 is 36 degrees (corresponding to a pitch of 3.5 mm (0.1378 inch) per revolution); D-6 is 32.5 degrees (corresponding to a pitch of 4.0 mm (0.1575 inch) per revolution); D-7 is 27 degrees (corresponding to a pitch of 5.0 mm (0.1969 inch) per revolution); D-8 is 23 degrees (corresponding to a pitch of 6.0 mm (0.2362 inch) per revolution); the portions 151 a, 151 b, 151 c, and 151 d of the helical path 151 includes 73, 23, 13, and 7 pairs, respectively, of the first and second cut shapes 128, 130; the radius of curvature of the cut 154 at the ends of the individual first, second, third, and fourth peaks 132, 134, 138, 139 is 0.02032 cm (0.008 inch); and the radius of curvature of the cut 154 where the second cut shape 130 meets the helical path 151 toward an adjacent second cut shape 130 is 0.0254 cm (0.010 inch). In other embodiments, the cut 154 can have other suitable dimensions, such as dimensions within about 10%, 20% or 30% of the dimensions in the illustrated embodiment. The width of the cut 154 can be, for example, from about 0.001016 cm (0.0004 inch) to about 0.003556 cm (0.0014 inch), from about 0.001524 cm (0.0006 inch) to about 0.003048 cm (0.0012 inch), or within another suitable range.

The features of the cut 160 shown in FIG. 18 can be similar to the features described above with reference to FIGS. 5, 8-10, and 13-16. For example, as shown in FIG. 18, the cut 160 can have dimensions D-8, E-8, F-8, and G-8. In the illustrated embodiment, at the individual portions 156 a, 156 b, 156 c, 156 d, 156 e, 156 f, 156 g, and 156 h of the helical path 156, D-8 is 36 degrees (corresponding to a pitch of 3.5 mm (0.1378 inch) per revolution), 32 degrees (corresponding to a pitch of 4.0 mm (0.1575 inch) per revolution), 27 degrees (corresponding to a pitch of 5.0 mm (0.1969 inch) per revolution), 23 degrees (corresponding to a pitch of 6.0 mm (0.2362 inch) per revolution), 20 degrees (corresponding to a pitch of 7.0 mm (0.2756 inch) per revolution), 17.7 degrees (corresponding to a pitch of 8.0 mm (0.315 inch) per revolution), 15.8 degrees (corresponding to a pitch of 9.0 mm (0.3543 inch) per revolution), and 15 degrees (corresponding to a pitch of 9.5 mm (0.374 inch) per revolution), respectively; at the individual portions 156 a-156 h of the helical path 156, E-8 is 0.01905 centimeter (0.0075 inch); at the individual portions 156 a, 156 b, 156 c, 156 d, 156 e, 156 f, 156 g, and 156 h of the helical path 156, G-8 is 0.07488 cm (0.02948 inch), 0.0635 cm (0.02500 inch), 0.07366 cm (0.02900 inch), 0.08103 cm (0.03190 inch), 0.07938 cm (0.03125 inch), 0.08192 cm (0.03225 inch), 0.08915 cm (0.03510 inch), and 0.08204 cm (0.03230 inch), respectively; at the individual portions 156 a, 156 b, and 156 c of the helical path 156, F-8 is 0.0254 cm (0.0100 inch), 0.02667 cm (0.0105 inch), and 0.03175 cm (0.0125 inch), respectively; at the individual portions 156 d-156 h of the helical path 156, F-8 is 0.0381 cm (0.0150 inch); the portions 156 a, 156 b, 156 c, 156 d, 156 e, 156 f, 156 g, and 151 h of the helical path 156 include 15, 14, 11, 9, 8, 7, 6, and 6 pairs, respectively, of the first and second cut shapes 128, 130; at the individual portions 156 a-156 h of the helical path 156, the radius of curvature of the cut 160 at the ends of the individual first, second, third, and fourth peaks 132, 134, 138, 139 is 0.02032 cm (0.008 inch); and the radius of curvature of the cut 160 where the second cut shape 130 meets the helical path 156 toward an adjacent first cut shape 128 is 0.0254 cm (0.01 inch). In other embodiments, the cut 160 can have other suitable dimensions, such as dimensions within about 10%, 20% or 30% of the dimensions in the illustrated embodiment. The width of the cut 160 can be, for example, from about 0.001016 cm (0.0004 inch) to about 0.003556 cm (0.0014 inch), from about 0.001524 cm (0.0006 inch) to about 0.003048 cm (0.0012 inch), or within another suitable range.

The cuts 166, 184, 195 shown in FIGS. 20, 22 and 24 include repeating series of cut shapes 168, 186, 196, respectively. Unlike the cuts 122, 147, 154, 160 described above with reference to FIGS. 5, 8-10, 13-16, and 18, the cuts 166, 184, 195 do not include alternating patterns of different types of cut shapes. Instead of using combinations of different types of cut shapes to impart resistance to complementary sets of fewer than all types of axial and torsional force that may act on a shaft segment, the individual cuts 166, 184, 195 may rely on a single type of cut shape that imparts resistance to all or nearly all types of axial and torsional force that may act on a shaft segment. This can be useful, for example, to allow such resistance to be imparted more gradually (e.g., at shorter increments) along a shaft segment than would be possible with combinations of different types of cut shapes. For example, a single type of cut shape that imparts resistance to all or nearly all types of axial and torsional force that may act on a shaft segment can often be disposed at a greater axial density than a comparable combination of cut shapes (e.g., a pair of the first and second cut shapes 128, 130 shown in FIGS. 5, 8-10, 13-16, and 18). In at least some cases, this may facilitate relatively gradual changes in flexibility along the longitudinal axis of a shaft segment.

With reference to FIG. 20, the cut shapes 168 can include a first peak 170 (e.g., a first finger), a second peak 172 (e.g., a second finger), and an interface 174 therebetween. The first and second peaks 170, 172 can curve away from the helical path 162 in different (e.g., opposite) directions. In the illustrated embodiment, the first peak 170 extends away from the helical path 162 to one side and the second peak 172 extends away from the helical path 162 to the opposite side. Both the first and second peaks 170, 172 begin extending from the helical path 162 oriented perpendicularly to the helical path 162. Further from the helical path 162, the first peak 170 transitions toward extending parallel to the helical path in a distally leaning direction and the second peak transitions toward extending parallel to the helical path in a proximally leaning direction. The first peak 170 partially encircles a first tab 176 and the second peak 172 partially encircles a second tab 178. As shown in FIG. 20, in the illustrated embodiment, the first and second peaks 170, 172 are rounded and hook-shaped. In other embodiments, the first and second peaks 170, 172 can have other suitable forms.

The cut 166 can have dimensions D-9 and G-9. In the illustrated embodiment, at the individual portions 162 a, 162 b, and 162 c of the helical path 162, D-9 is 36 degrees (corresponding to a pitch of 3.5 mm (0.1378 inch) per revolution), 32 degrees (corresponding to a pitch of 4.0 mm (0.1575 inch) per revolution), and 27 degrees (corresponding to a pitch of 5.0 mm (0.1969 inch) per revolution), respectively; G-9 is 0.1092 cm (0.043 inch), 0.1499 cm (0.059 inch), and 0.1524 cm (0.060 inch), respectively; the individual portions 164 a, 164 b, and 164 c of the helical path 162 include 70, 49, and 37, respectively, of the cut shapes 168; and the radius of curvature of the individual first and second tabs 176, 178 is 0.0127 cm (0.005 inch). In other embodiments, the cut 166 can have other suitable dimensions, such as dimensions within about 10%, 20% or 30% of the dimensions in the illustrated embodiment. The width of the cut 166 can be, for example, from about 0.001016 cm (0.0004 inch) to about 0.003556 cm (0.0014 inch), from about 0.001524 cm (0.0006 inch) to about 0.003048 cm (0.0012 inch), or within another suitable range.

With reference to FIG. 22, the cut shapes 186 can include a single peak 188 (e.g., a finger) that extends away from the helical path 180 and defines a tab 190 having a neck 191 and a head 192, with the head 192 being positioned further from the helical path 180 than the neck 191. The neck 191 can be narrower than the head 192 along a line parallel to the helical path 180. This configuration can allow portions of the shaft segment 182 along opposite sides of the cut 184 to at least partially interlock thereby preventing or reducing undesirable widening of the cut 184. The peaks 188 and the tabs 190 can extend away from the helical path 180 in the same direction from one cut shape 186 to the next along the helical path 180. For example, in the illustrated embodiment, the peaks 188 and the tabs 190 extend away from the helical path 180 leaning proximally. In other embodiments, the peaks 188 and the tabs 190 can extend away from the helical path 180 leaning distally. In still other embodiments, the peaks 188 and the tabs 190 can extend away from the helical path 180 in different (e.g., opposite) directions from one cut shape 186 to the next along the helical path 180.

The cut 184 can have dimensions D-10, G-10, H-10, I-10, and J-10. H-10 is the distance from the helical path 180 to a focal centerpoint of a curved portion of the cut shape 186 adjacent to the head 192. I-10 is the distance between focal centerpoints of curved portions of the cut shape 186 adjacent to opposite sides of the transition between the head 192 and the neck 191. J-10 is the distance between focal centerpoints of curved portions of the cut shape 186 adjacent to opposite sides of the neck 191. In the illustrated embodiment, at the individual portions 182 a, 182 b, and 182 c of the helical path 182, D-10 is 29.5 degrees (corresponding to a pitch of 4.5 mm (0.1772 inch) per revolution), 27 degrees (corresponding to a pitch of 5.0 mm (0.1969 inch) per revolution), and 24.9 degrees (corresponding to a pitch of 5.5 mm (0.2165 inch) per revolution), respectively; at the individual portions 182 a, 182 b, and 182 c of the helical path 182, G-10 is 1.098 mm (0.04323 inch), 1.488 mm (0.05858 inch), and 1.523 mm (0.05996 inch), respectively; at the individual portions 182 a-182 c of the helical path 182, H-10 is 0.225 mm (0.008858 inch); at the individual portions 182 a-182 c of the helical path 182, I-10 is 0.697 mm (0.02744 inch); at the individual portions 182 a-182 c of the helical path 182, J-10 is 0.706 mm (0.0278 inch); the individual portions 182 a, 182 b, and 182 c of the helical path 182 include 70, 49, and 37, respectively, of the cut shapes 186; at the individual portions 182 a, 182 b, and 182 c of the helical path 182, the radius of curvature of the curved portion of the cut shape 186 adjacent to the head 192 is 1.016 cm (0.400 inch); and at the individual portions 182 a, 182 b, and 182 c of the helical path 182, the radius of curvature of the curved portions of the cut shape 186 adjacent to opposite sides of the neck 191 are 0.127 cm (0.050 inch). In other embodiments, the cut 184 can have other suitable dimensions, such as dimensions within about 10%, 20% or 30% of the dimensions in the illustrated embodiment. The width of the cut 184 can be, for example, from about 0.001016 cm (0.0004 inch) to about 0.003556 cm (0.0014 inch), from about 0.001524 cm (0.0006 inch) to about 0.003048 cm (0.0012 inch), or within another suitable range.

With reference to FIG. 24, the cut shapes 196 can include a single peak 197 (e.g., a finger) that extends away from the helical path 193 and defines a tab 198 having a neck 199 and a head 200, with the head 200 being positioned further from the helical path 193 than the neck 199. The neck 199 can be narrower than the head 200 along a line parallel to the helical path 193. Similar to the configuration shown in FIG. 22, the configuration shown in FIG. 24 can allow portions of the shaft segment 194 along opposite sides of the cut 195 to at least partially interlock thereby preventing or reducing undesirable widening of the cut 195. The peaks 197 and the tabs 198 can extend away from the helical path 193 in the same direction from one cut shape 196 to the next along the helical path 193. For example, in the illustrated embodiment, the peaks 197 and the tabs 198 extend away from the helical path 193 leaning proximally. In other embodiments, the peaks 197 and the tabs 198 can extend away from the helical path 193 leaning distally. In still other embodiments, the peaks 197 and the tabs 198 can extend away from the helical path 193 in different (e.g., opposite) directions from one cut shape 196 to the next along the helical path 193. In contrast to the cut shapes 186 shown in FIG. 22, the heads 200 of the cut shapes 196 can be flat rather than rounded. The individual tabs 198 and corresponding cut shapes 196 can comprise a wedge-shaped arrangement with the tabs 198 including a wedge-shaped portion (i.e., a “tail”) at the head 200 and a restricted portion at the neck 199. The cut shapes 196 can form recesses or sockets (i.e., “tail sockets”) complementary to the tabs 198. In some embodiments, the tabs 198 and cut shapes 196 may fit snugly with very little room between the portions of the shaft segment 194 at opposite sides of the cut 195. In other embodiments, however, there may be some space between at least a portion of at least some of the wedge-shaped portions and the complementary sockets, such as to allow some amount of relative movement between the portions of the shaft segment 194 at opposite sides of the cut 195.

The cut 195 can have dimensions D-11, G-11, K-11, and L-11. In the illustrated embodiment, at the individual portions 193 a, 193 b, and 193 c of the helical path 193, D-11 is 29.5 degrees (corresponding to a pitch of 4.5 mm (0.1772 inch) per revolution), 27 degrees (corresponding to a pitch of 5.0 mm (0.1969 inch) per revolution), and 24.9 degrees (corresponding to a pitch of 5.5 mm (0.2165 inch) per revolution), respectively; at the individual portions 193 a, 193 b, and 193 c of the helical path 193, G-11 is 1.055 mm (0.04154 inch), 1.450 mm (0.05709 inch), and 1.510 mm (0.05945 inch), respectively; at the individual portions 193 a-193 c of the helical path 193, K-11 is 0.245 mm (0.009646 inch); at the individual portions 193 a-193 c of the helical path 193, L-11 is 0.800 mm (0.0315 inch); and the individual portions 193 a, 193 b, and 193 c of the helical path 193 include 70, 49, and 37, respectively, of the cut shapes 196. In other embodiments, the cut 195 can have other suitable dimensions, such as dimensions within about 10%, 20% or 30% of the dimensions in the illustrated embodiment. The width of the cut 195 can be, for example, from about 0.001016 cm (0.0004 inch) to about 0.003556 cm (0.0014 inch), from about 0.001524 cm (0.0006 inch) to about 0.003048 cm (0.0012 inch), or within another suitable range.

With reference to FIGS. 3-24 together, although the helical paths 126, 146, 148, 151, 156, 162, 180, 193 the shaft segments 127, 143, 149, 153, 158, 164, 182, 194, and the cuts 122, 147, 154, 160, 166, 184, 195 are illustrated in specific combinations in FIGS. 3-24, other combinations are also possible. For example, the individual cuts 122, 147, 154, 160, 166, 184, 195 shown in FIGS. 4, 5, 8-10, 13-16, 18, 20, 22 and 24 can be used in conjunction with any of the helical paths 126, 146, 148, 151, 156, 162, 180, 193 shown in FIGS. 3, 7A, 11, 12A, 17, 19, 21 and 23.

FIGS. 25-28 are two-dimensional representations of portions of cuts configured in accordance with several embodiments of the present technology. As shown in FIG. 25, for example, in some embodiments a shaft 108 includes an uncut region 201 with the first and second cut shapes 128, 130 positioned along portions of a helical path on either side of the uncut region 201. For example, the uncut region 201 can be one of many uncut regions 201 interspersed among the first and second cut shapes 128, 130 along the helical path. In other embodiments, the first and second cut shapes 128, 130 can be portions of a continuous cut. For example, as shown in FIG. 26, the first and second cut shapes 128, 130 can be in suitable patterns along the helical path other than one-to-one alternating patterns. Suitable patterns can include, for example, random patterns, non-random patterns, two-to-one alternating patterns, two-to-two alternating patterns, and three-to-two alternating patterns, among others. Furthermore, the spacing between adjacent first and second cut shapes 128, 130 can be consistent or variable.

Referring next to FIG. 27, a shaft can include two or more cut shapes 202 and two or more cut shapes 204 interspersed along a helical path. Similar to the cut shapes 168, 186 shown in FIGS. 20 and 22, the individual cut shapes 202 can be configured to fully interlock rather than partially interlock. For example, the individual cut shapes 202 can be configured to at least partially resist deformation in response to compression on the shaft, tension on the shaft, torsion on the shaft in the first circumferential direction, and torsion on the shaft in the second circumferential direction. The shaft, for example, can include tabs 206 (e.g., protrusions, lobes, or other suitable structures) adjacent to the cut shapes 202, with the cut shapes 202 defining the tabs 106 by forming recesses complementary to the tabs 206. The individual tabs 206 can include a flared portion 206 a (e.g., a rounded head portion) and a restricted portion 206 b (e.g., a rounded neck portion), or other suitable structures. The cut shapes 204 can be sinusoidal and have amplitudes oriented perpendicularly to the helical path. For example, the individual cut shapes 204 can include a first peak 208 and a second peak 210 with an interface 212 therebetween that is diagonal relative to a longitudinal axis of the shaft and perpendicular to the helical path.

As shown in FIG. 28, in some embodiments a shaft includes the cut shapes 202 without the cut shapes 204. In other embodiments, the shaft can include the cut shapes 204 without the cut shapes 202. Although the cut shapes 202, 204 are potentially useful alone or in combination with other cut shapes, it is expected that combinations of the first and second cut shapes 128, 130 may be more stable in some cases than the cut shapes 202, 204 alone or in combination during use of a neuromodulation catheter. For example, is it expected that combinations of cut shapes that impart resistance to complementary sets of fewer than all types of axial and torsional force that may act on a shaft during use of a neuromodulation catheter may facilitate dissipation of localized stresses along a cut. Similar to the cut shapes 168, 186 shown in FIGS. 20 and 22, however, the cut shapes 202, 204 may advantageously allow for relatively gradual changes in flexibility along the length of a shaft segment. It will further be appreciated that catheters configured in accordance with embodiments of the present technology can include various combinations of cut shapes tailored to provide a desired level of flexibility and/or control for different applications.

FIGS. 29-31 are perspective views of shaft segments having guide wire exit openings with different positions relative to cuts configured in accordance with several embodiments of the present technology. For example, with reference to FIGS. 5 and 29, in some embodiments a shaft segment 214 having the first and second cut shapes 128, 130 has a guide wire exit opening 216 in place of a third peak 138 of one of the second cut shapes 130. In other embodiments, the guide wire exit opening 216 can be in place of the first peak 132, the second peak 134, the fourth peak 139, or a combination thereof including or not including the third peak 138. As another example, with reference to FIGS. 5 and 30, a shaft segment 218 having the first and second cut shapes 128, 130 can have a guide wire exit opening 220 between (e.g., about evenly between) adjacent turns of a helical path along which the first and second cut shapes 128, 130 are distributed. As yet another example, with reference to FIGS. 5, 25 and 31, a shaft segment 222 having the first and second cut shapes 128, 130 and the uncut region 201 (e.g., as described above with reference to FIG. 25) can have a guide wire exit opening 224 at the uncut region 201. In other examples, the guide wire exit openings may have other suitable positions relative to the cuts. Furthermore, although the guide wire exit openings 216, 220, 224 are illustrated in FIGS. 29-31 as generally oval with their longitudinal axes aligned with longitudinal axes of the corresponding shaft segments 214, 218, 222, the guide wire exit openings 216, 220, 224 can have other suitable shapes and/or orientations.

Instead of or in addition to a cut tube, neuromodulation catheters configured in accordance with at least some embodiments of the present technology can include one or more elongate members (e.g., filaments, wires, ribbons, or other suitable structures) helically wound into one or more tubular shapes. Similar to the axial density of features of a cut along a longitudinal axis of a shaft (e.g., as discussed above with reference to FIG. 3), the axial density of windings of a helically wound elongate member along a longitudinal axis of a shaft can be selected to change the flexibility of the shaft. For example, an axial density of windings along a longitudinal axis of a shaft can be selected to facilitate intravascular delivery of a neuromodulation element to a treatment location within or otherwise proximate to a renal artery of a human patient via a transradial or other suitable approach. In some embodiments, an axial density of windings along a longitudinal axis of a shaft varies along the length of the shaft (e.g., to tailor the shaft to the tortuosity or other geometry of different portions of a transradial or other suitable approach). In other embodiments, the axial density of windings along a longitudinal axis of a shaft can be consistent along the length of the shaft (e.g., to increase the overall flexibility of the shaft).

FIGS. 32 and 33 are perspective views of shaft segments including helically wound elongate members configured in accordance with several embodiments of the present technology. With reference to FIG. 32, a shaft 250 can include a first helically wound elongate member 252 having a series of first windings 254 at least partially forming a first tubular structure 256. The shaft 250 can further include a second helically wound elongate member 258 having a series of second windings 260 at least partially forming a second tubular structure 262. The first tubular structure 256 can be disposed within the second tubular structure 262, and the first and second tubular structures 256, 262 can be concentric.

In some embodiments, at least one of the first and second helically wound elongate members 252, 258 is multifilar. For example, in the embodiment shown in FIG. 32, the second helically wound elongate member 258 is multifilar with five parallel filaments (individually identified in FIG. 32 as 258 a-e), and the first helically wound elongate member 252 is monofilar. In other embodiments, the second helically wound elongate member 258 can be monofilar and the first helically wound elongate member 252 can be multifilar. In still other embodiments, both the first and second helically wound elongate members 252, 258 can be monofilar or multifilar. Furthermore, in some embodiments, the first windings 254, the second windings 260, or both are “openly wound” or spaced apart along a longitudinal axis of the shaft 250. For example, in the embodiment shown in FIG. 32, the second windings 260 are shown spaced apart along the longitudinal axis of the shaft 250 with gaps 181 between adjacent second windings 260, and the first windings 254 are shown not spaced apart along the longitudinal axis of the shaft 250. In other embodiments, the second windings 260 can be not spaced apart along the longitudinal axis of the shaft 250 and the first windings 254 can be spaced apart along the longitudinal axis of the shaft 250. In still other embodiments, both the first and second windings 254, 260 can be spaced apart or not spaced apart along the longitudinal axis of the shaft 250.

With reference to FIG. 33, a shaft 264 can include a third helically wound elongate member 266 having a series of third windings 268 at least partially forming a third tubular structure 270. The first and second tubular structures 256, 262 can be disposed within the third tubular structure 270, and the first, second, and third tubular structures 256, 262, 270 can be concentric. In the embodiment shown in FIG. 33, the third helically wound elongate member 266 is multifilar with parallel filaments (individually identified in FIG. 33 as 266 a-e). In other embodiments, the third helically wound elongate member 266 can be monofilar. Furthermore, in embodiments having more than one helically wound layer, the layers may be counter-wound, e.g. a right-hand helical layer may surround a left-hand helical layer. The shaft 264 can further include biocompatible jacket 272 at least partially encasing the first, second, and third tubular structures 256, 262, 270. The biocompatible jacket 272, for example, can be at least partially made of a smooth polymer or other suitable material well suited for sliding contact with an inner wall of a body lumen.

FIGS. 34 and 35 are side profile views of helically wound elongate members 274, 278, respectively, configured in accordance with several embodiments of the present technology. With reference to FIG. 34, the helically wound elongate member 274 can have a series of windings 276 with an average helix angle K-1. With reference to FIG. 34, the helically wound elongate member 278 can have a series of windings 280 with an average helix angle K-2. With reference to FIGS. 33-35 together, the first windings 254, the second windings 260, the third windings 268, or a subset thereof, can have different average helix angles. For example, a first average helix angle of the first windings 254 can be different than a second average helix angle of the second windings 260 by an angle within a range from about 10 degrees to about 140 degrees (e.g., a range from about 30 degrees to about 120 degrees, or another suitable range). Similarly, the first average helix angle of the first windings 254 can be different than a third average helix angle of the third windings 268 by an angle within a range from about 10 degrees to about 140 degrees (e.g., a range from about 30 degrees to about 120 degrees, or another suitable range) and the second average helix angle of the second windings 260 can be between (e.g., about midway between) the first and third average helix angles of the first and third windings 254, 268, respectively.

FIG. 36 is a side profile view of a helically wound elongate member 282 configured in accordance with an embodiment of the present technology. The helically wound elongate member 282 can have a series of windings 284 with different average helix angles and opposite chirality on either side of a transition region 286. Although an abrupt change in average helix angle at the transition region 286 is shown in FIG. 36, the change at the transition region 286 can alternatively be gradual or incremental. With reference to FIGS. 32, 33 and 36 together, in some embodiments the first windings 254, the second windings 260, and/or the third windings 268 include one or more transition regions 286. In other embodiments, the first windings 254, the second windings 260, and the third windings 268 can have consistent helix angles along the length of the shaft 250. Including one or more transition regions 286 can be useful, for example, to allow a difference between average helix angles of windings within concentric tubular structures to vary (e.g., to change at least once) along the length of the shaft 250. For example, this difference can decrease (e.g., abruptly, gradually, or incrementally) distally along the length of the shaft 250. It is expected that increasing a difference between average helix angles of windings within concentric tubular structures may reduce flexibility and increase axial and torsional stiffness of a shaft, and that decreasing a difference between average helix angles of windings within concentric tubular structures may increase flexibility and decrease axial and torsional stiffness of a shaft. Accordingly, the positions of the transition regions 286 can be selected to change the flexibility of the shaft relative to the axial and torsional stiffness of the shaft along the length of a shaft (e.g., to facilitate intravascular delivery of a neuromodulation element to a treatment location within or otherwise proximate to a renal artery of a human patient via a transradial or other suitable approach).

Instead of or in addition to a cut tube and/or a helically wound elongate member, neuromodulation catheters configured in accordance with at least some embodiments of the present technology can include shafts having one or more segments with different shape memory properties. With reference to FIG. 3, for example, the first portion 127 a of the segment 127 can be made at least partially of a first shape-memory alloy, the second portion 127 b of the segment 127 can be made at least partially of a second shape-memory alloy, and the third portion 127 c of the segment 127 can be made at least partially of a third shape-memory alloy. The first, second, and third shape-memory alloys can be different or the same. In some embodiments, the first, second, and third shape-memory alloys are nitinol. In other embodiments, the first, second, and third shape-memory alloys can be other suitable materials. The first, second, and third shape-memory alloys can have first, second, and third shape-memory transformation temperature ranges, respectively. For example, when the first, second, and third shape-memory alloys are nitinol, the first, second, and third shape-memory transformation temperature ranges can include Af temperatures.

The third shape-memory transformation temperature range and/or an Af temperature of the third shape-memory transformation temperature range can be lower than the first shape-memory transformation temperature range and/or an Af temperature of the first shape-memory transformation temperature range. For example, the first shape-memory transformation temperature range can include an Af temperature greater than body temperature and the third shape-memory transformation temperature range includes an Af temperature less than body temperature. A shape-memory transformation temperature range and/or an Af temperature of a shape-memory transformation temperature range of the shaft 108 can increase (e.g., abruptly, gradually, or incrementally) along the second portion 127 b of the segment 127 from the third portion 127 c of the segment 127 toward the first portion 127 a of the segment 127. In some embodiments, to vary the shape-memory transformation temperature ranges and/or Af temperatures along the length of the shaft 108, the first, second, and third portions 127 a-c of the segment 127 are formed separately and then joined. In other embodiments, the shape-memory transformation temperature ranges and/or the Af temperatures along the length of the shaft 108 can be achieved by processing the first, second, and third portions 127 a-c of the segment 127 differently while they are joined. For example, one of the first, second, and third portions 127 a-c can be subjected to a heat treatment to change its shape-memory transformation temperature range and/or Af temperature while the others of the first, second, and third portions 127 a-c are thermally insulated.

It is expected that greater shape-memory transformation temperature ranges and/or Af temperatures of shape-memory transformation temperature ranges may increase flexibility and decrease axial and torsional stiffness of a shaft (e.g., by causing nitinol to tend to assume a austenite phase at body temperature), and that lower shape-memory transformation temperature ranges and/or Af temperatures of shape-memory transformation temperature ranges may decrease flexibility and increase axial and torsional stiffness of a shaft (e.g., by causing nitinol to tend to assume a martensite phase at body temperature). Accordingly, the positions of portions of a shaft having different shape-memory transformation temperature ranges and/or Af temperatures of shape-memory transformation temperature ranges can be selected to change the flexibility of the shaft relative to the axial and torsional stiffness of the shaft along the length of a shaft (e.g., to facilitate intravascular delivery of a neuromodulation element to a treatment location within or otherwise proximate to a renal artery of a human patient via a transradial or other suitable approach).

Renal Neuromodulation

Renal neuromodulation is the partial or complete incapacitation or other effective disruption of nerves of the kidneys (e.g., nerves terminating in the kidneys or in structures closely associated with the kidneys). In particular, renal neuromodulation can include inhibiting, reducing, and/or blocking neural communication along neural fibers (e.g., efferent and/or afferent neural fibers) of the kidneys. Such incapacitation can be long-term (e.g., permanent or for periods of months, years, or decades) or short-term (e.g., for periods of minutes, hours, days, or weeks). Renal neuromodulation is expected to contribute to the systemic reduction of sympathetic tone or drive and/or to benefit at least some specific organs and/or other bodily structures innervated by sympathetic nerves. Accordingly, renal neuromodulation is expected to be useful in treating clinical conditions associated with systemic sympathetic overactivity or hyperactivity, particularly conditions associated with central sympathetic overstimulation. For example, renal neuromodulation is expected to efficaciously treat hypertension, heart failure, acute myocardial infarction, metabolic syndrome, insulin resistance, diabetes, left ventricular hypertrophy, chronic and end stage renal disease, inappropriate fluid retention in heart failure, cardio-renal syndrome, polycystic kidney disease, polycystic ovary syndrome, osteoporosis, erectile dysfunction, and sudden death, among other conditions.

Renal neuromodulation can be electrically-induced, thermally-induced, chemically-induced, or induced in another suitable manner or combination of manners at one or more suitable treatment locations during a treatment procedure. The treatment location can be within or otherwise proximate to a renal lumen (e.g., a renal artery, a ureter, a renal pelvis, a major renal calyx, a minor renal calyx, or another suitable structure), and the treated tissue can include tissue at least proximate to a wall of the renal lumen. For example, with regard to a renal artery, a treatment procedure can include modulating nerves in the renal plexus, which lay intimately within or adjacent to the adventitia of the renal artery.

Renal neuromodulation can include a cryotherapeutic treatment modality alone or in combination with another treatment modality. Cryotherapeutic treatment can include cooling tissue at a treatment location in a manner that modulates neural function. For example, sufficiently cooling at least a portion of a sympathetic renal nerve can slow or potentially block conduction of neural signals to produce a prolonged or permanent reduction in renal sympathetic activity. This effect can occur as a result of cryotherapeutic tissue damage, which can include, for example, direct cell injury (e.g., necrosis), vascular or luminal injury (e.g., starving cells from nutrients by damaging supplying blood vessels), and/or sublethal hypothermia with subsequent apoptosis. Exposure to cryotherapeutic cooling can cause acute cell death (e.g., immediately after exposure) and/or delayed cell death (e.g., during tissue thawing and subsequent hyperperfusion). Neuromodulation using a cryotherapeutic treatment in accordance with embodiments of the present technology can include cooling a structure proximate an inner surface of a body lumen wall such that tissue is effectively cooled to a depth where sympathetic renal nerves reside. For example, in some embodiments, a cooling assembly of a cryotherapeutic device can be cooled to the extent that it causes therapeutically-effective, cryogenic renal neuromodulation. In other embodiments, a cryotherapeutic treatment modality can include cooling that is not configured to cause neuromodulation. For example, the cooling can be at or above cryogenic temperatures and can be used to control neuromodulation via another treatment modality (e.g., to protect tissue from neuromodulating energy).

Renal neuromodulation can include an electrode-based or transducer-based treatment modality alone or in combination with another treatment modality. Electrode-based or transducer-based treatment can include delivering electricity and/or another form of energy to tissue at a treatment location to stimulate and/or heat the tissue in a manner that modulates neural function. For example, sufficiently stimulating and/or heating at least a portion of a sympathetic renal nerve can slow or potentially block conduction of neural signals to produce a prolonged or permanent reduction in renal sympathetic activity. A variety of suitable types of energy can be used to stimulate and/or heat tissue at a treatment location. For example, neuromodulation in accordance with embodiments of the present technology can include delivering RF energy, pulsed energy, microwave energy, optical energy, focused ultrasound energy (e.g., high-intensity focused ultrasound energy), or another suitable type of energy alone or in combination. An electrode or transducer used to deliver this energy can be used alone or with other electrodes or transducers in a multi-electrode or multi-transducer array. Furthermore, the energy can be applied from within the body (e.g., within the vasculature or other body lumens in a catheter-based approach) and/or from outside the body (e.g., via an applicator positioned outside the body). Furthermore, energy can be used to reduce damage to non-targeted tissue when targeted tissue adjacent to the non-targeted tissue is subjected to neuromodulating cooling.

Neuromodulation using focused ultrasound energy (e.g., high-intensity focused ultrasound energy) can be beneficial relative to neuromodulation using other treatment modalities. Focused ultrasound is an example of a transducer-based treatment modality that can be delivered from outside the body. Focused ultrasound treatment can be performed in close association with imaging (e.g., magnetic resonance, computed tomography, fluoroscopy, ultrasound (e.g., intravascular or intraluminal), optical coherence tomography, or another suitable imaging modality). For example, imaging can be used to identify an anatomical position of a treatment location (e.g., as a set of coordinates relative to a reference point). The coordinates can then entered into a focused ultrasound device configured to change the power, angle, phase, or other suitable parameters to generate an ultrasound focal zone at the location corresponding to the coordinates. The focal zone can be small enough to localize therapeutically-effective heating at the treatment location while partially or fully avoiding potentially harmful disruption of nearby structures. To generate the focal zone, the ultrasound device can be configured to pass ultrasound energy through a lens, and/or the ultrasound energy can be generated by a curved transducer or by multiple transducers in a phased array (curved or straight).

Heating effects of electrode-based or transducer-based treatment can include ablation and/or non-ablative alteration or damage (e.g., via sustained heating and/or resistive heating). For example, a treatment procedure can include raising the temperature of target neural fibers to a target temperature above a first threshold to achieve non-ablative alteration, or above a second, higher threshold to achieve ablation. The target temperature can be higher than about body temperature (e.g., about 37° C.) but less than about 45° C. for non-ablative alteration, and the target temperature can be higher than about 45° C. for ablation. Heating tissue to a temperature between about body temperature and about 45° C. can induce non-ablative alteration, for example, via moderate heating of target neural fibers or of vascular or luminal structures that perfuse the target neural fibers. In cases where vascular structures are affected, the target neural fibers can be denied perfusion resulting in necrosis of the neural tissue. Heating tissue to a target temperature higher than about 45° C. (e.g., higher than about 60° C.) can induce ablation, for example, via substantial heating of target neural fibers or of vascular or luminal structures that perfuse the target fibers. In some patients, it can be desirable to heat tissue to temperatures that are sufficient to ablate the target neural fibers or the vascular or luminal structures, but that are less than about 90° C. (e.g., less than about 85° C., less than about 80° C., or less than about 75° C.).

Renal neuromodulation can include a chemical-based treatment modality alone or in combination with another treatment modality. Neuromodulation using chemical-based treatment can include delivering one or more chemicals (e.g., drugs or other agents) to tissue at a treatment location in a manner that modulates neural function. The chemical, for example, can be selected to affect the treatment location generally or to selectively affect some structures at the treatment location over other structures. The chemical, for example, can be guanethidine, ethanol, phenol, a neurotoxin, or another suitable agent selected to alter, damage, or disrupt nerves. A variety of suitable techniques can be used to deliver chemicals to tissue at a treatment location. For example, chemicals can be delivered via one or more needles originating outside the body or within the vasculature or other body lumens. In an intravascular example, a catheter can be used to intravascularly position a therapeutic element including a plurality of needles (e.g., micro-needles) that can be retracted or otherwise blocked prior to deployment. In other embodiments, a chemical can be introduced into tissue at a treatment location via simple diffusion through a body lumen wall, electrophoresis, or another suitable mechanism. Similar techniques can be used to introduce chemicals that are not configured to cause neuromodulation, but rather to facilitate neuromodulation via another treatment modality.

Returning to FIG. 1, in another embodiment, the system 100 may be a stent delivery system. For example, the catheter 102 can be a stent delivery catheter and the neuromodulation element can 112 be a stent delivery element. The stent delivery element can include a dilatation balloon (not shown) with a balloon expandable stent disposed thereon. The stent delivery catheter also can include the handle 110 operably connected to the shaft 108 via the proximal end portion 108 a. The shaft 108 can be configured to locate the stent delivery element intravascularly at a treatment location within or otherwise proximate to a body lumen (e.g., coronary artery). The handle 110 can be configured to aid in the delivery and deployment of the stent to the treatment location. The stent delivery system may, in at least some cases, be without the console 104 or the cable 106.

The stent of stent delivery element may be any balloon expandable stent as known to one of ordinary skill in the art. In one embodiment, for example, the stent is formed from a single wire forming a continuous sinusoid. The stent may include a coating disposed on the surface of the stent. The coating may include a polymer and/or a therapeutic agent. In one embodiment, the coating includes a Biolinx™ polymer blended with a limus drug. In another embodiment, the stent is a drug filled stent having a lumen filled with a therapeutic agent. Other configurations are also possible, such as configurations in which the stent delivery element does not include a stent disposed on a dilatation balloon.

CONCLUSION

This disclosure is not intended to be exhaustive or to limit the present technology to the precise forms disclosed herein. Although specific embodiments are disclosed herein for illustrative purposes, various equivalent modifications are possible without deviating from the present technology, as those of ordinary skill in the relevant art will recognize. In some cases, well-known structures and functions have not been shown and/or described in detail to avoid unnecessarily obscuring the description of the embodiments of the present technology. Although steps of methods may be presented herein in a particular order, in alternative embodiments the steps may have another suitable order. Similarly, certain aspects of the present technology disclosed in the context of particular embodiments can be combined or eliminated in other embodiments. Furthermore, while advantages associated with certain embodiments may have been disclosed in the context of those embodiments, other embodiments can also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages or other advantages disclosed herein to fall within the scope of the present technology. Accordingly, this disclosure and associated technology can encompass other embodiments not expressly shown and/or described herein.

Throughout this disclosure, the singular terms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. Similarly, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Additionally, the terms “comprising” and the like are used throughout this disclosure to mean including at least the recited feature(s) such that any greater number of the same feature(s) and/or one or more additional types of features are not precluded. Directional terms, such as “upper,” “lower,” “front,” “back,” “vertical,” and “horizontal,” may be used herein to express and clarify the relationship between various elements. It should be understood that such terms do not denote absolute orientation. Reference herein to “one embodiment,” “an embodiment,” or similar formulations means that a particular feature, structure, operation, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present technology. Thus, the appearances of such phrases or formulations herein are not necessarily all referring to the same embodiment. Furthermore, various particular features, structures, operations, or characteristics may be combined in any suitable manner in one or more embodiments. 

I/We claim:
 1. A neuromodulation catheter, comprising: an elongate shaft including— two or more first cut shapes, the first cut shapes being configured to at least partially resist deformation in response to compression on the shaft along a longitudinal axis of the shaft, tension on the shaft along the longitudinal axis, and torsion on the shaft in a first circumferential direction perpendicular to the longitudinal axis, and two or more second cut shapes, the second cut shapes being configured to at least partially resist deformation in response to compression on the shaft along the longitudinal axis, torsion on the shaft in the first circumferential direction, and torsion on the shaft in a second circumferential direction opposite to the first circumferential direction; and a neuromodulation element operably connected to the shaft via a distal end portion of the shaft, wherein— the first and second cut shapes are interspersed along a helical path extending about the longitudinal axis, the first cut shapes are less resistant to deformation in response to torsion on the shaft in the second circumferential direction than are the second cut shapes, and the second cut shapes are less resistant to deformation in response to tension on the shaft along the longitudinal axis than are the first cut shapes.
 2. The neuromodulation catheter of claim 1 wherein: the shaft includes a hypotube having a wall thickness; and the first and second cut shapes extend at least partially through the wall thickness of the hypotube.
 3. The neuromodulation catheter of claim 1 wherein the first and second cut shapes alternate along the helical path in a pattern.
 4. The neuromodulation catheter of claim 1 wherein the first and second cut shapes are portions of a continuous cut.
 5. The neuromodulation catheter of claim 1 wherein: the first cut shapes are sinusoidal and have amplitudes with a first orientation relative to the longitudinal axis; and the second cut shapes are sinusoidal and have amplitudes with a second orientation relative to the longitudinal axis, the second orientation being different than the first orientation.
 6. The neuromodulation catheter of claim 1 wherein an axial density of the first and second cut shapes along the longitudinal axis is selected to facilitate intravascular delivery of the neuromodulation element to a treatment location within or otherwise proximate to a renal artery of a human patient via a transradial approach.
 7. The neuromodulation catheter of claim 1 wherein: the helical path extends along a portion of the longitudinal axis corresponding to a segment of the shaft; and a distance along the longitudinal axis between the neuromodulation element and the segment is selected to cause the segment to be at least proximate to a relatively sharply angled or otherwise relatively tortuous region of a transradial approach when the neuromodulation element is operably positioned at a treatment location within or otherwise proximate to a renal artery of a human patient.
 8. The neuromodulation catheter of claim 7 wherein the relatively sharply angled or otherwise relatively tortuous region is within or otherwise proximate to a subclavian artery of a human patient.
 9. The neuromodulation catheter of claim 1 wherein: the shaft includes an uncut region; and the first and second cut shapes are positioned along portions of the helical path on either side of the uncut region.
 10. The neuromodulation catheter of claim 9 wherein the shaft includes a guide wire exit opening at the uncut region.
 11. The neuromodulation catheter of claim 1 wherein: the shaft includes a hypotube having a wall thickness; the first and second cut shapes extend at least partially through the wall thickness of the hypotube at a first segment of the shaft, the first segment being within about 3 centimeters of the neuromodulation element and having a length from about 30 centimeters to about 80 centimeters; the shaft includes a second segment proximal to the first segment, the second segment having a length greater than about 40 centimeters; and the hypotube is less resistant to deflection in response to lateral force at the first segment than at the second segment.
 12. The neuromodulation catheter of claim 11 wherein the hypotube is uncut at the second segment.
 13. The neuromodulation catheter of claim 11 wherein: the first segment has a length from about 40 centimeters to about 70 centimeters; and the second segment has a length greater than about 50 centimeters.
 14. The neuromodulation catheter of claim 11 wherein an axial density of the first and second cut shapes is consistent along the length of the first segment.
 15. The neuromodulation catheter of claim 11 wherein an axial density of the first and second cut shapes decreases along at least a portion of the length of the first segment toward the second segment.
 16. The neuromodulation catheter of claim 15 wherein the axial density of the first and second cut shapes decreases gradually along the entire length of the first segment toward the second segment.
 17. The neuromodulation catheter of claim 15 wherein: the individual first cut shapes include a first peak and a second peak with a first interface therebetween; the individual second cut shapes include a third peak and a fourth peak with a second interface therebetween; an angle between the first interface and the longitudinal axis is greater than an angle between the second interface and the longitudinal axis; and lengths of the second interfaces increase along at least a portion of the length of the first segment toward the second segment.
 18. The neuromodulation catheter of claim 17 wherein: the axial density of the first and second cut shapes decreases gradually along the entire length of the first segment toward the second segment; and the lengths of the second interfaces increase gradually along the entire length of the first segment toward the second segment.
 19. The neuromodulation catheter of claim 1 wherein: the individual first cut shapes include a first peak and a second peak with a first interface therebetween; the individual second cut shapes include a third peak and a fourth peak with a second interface therebetween; and an angle between the first interface and the longitudinal axis is greater than an angle between the second interface and the longitudinal axis.
 20. The neuromodulation catheter of claim 19 wherein the shaft includes a guide wire exit opening in place of the first peak, the second peak, the third peak, the fourth peak, or a combination thereof.
 21. The neuromodulation catheter of claim 19 wherein: the first interface is perpendicular to the longitudinal axis; and the second interface is parallel to the longitudinal axis.
 22. A neuromodulation catheter, comprising: an elongate shaft extending along a longitudinal axis, the shaft including— two or more sinusoidal first cut shapes having amplitudes with a first orientation relative to the longitudinal axis, and two or more sinusoidal second cut shapes having amplitudes with a second orientation relative to the longitudinal axis, the second orientation being different than the first orientation; and a neuromodulation element operably connected to the shaft via a distal end portion of the shaft, wherein the first and second cut shapes are interspersed along a helical path extending about the longitudinal axis.
 23. The neuromodulation catheter of claim 22 wherein the orientation of the first cut shapes is perpendicular to the orientation of the second cut shapes.
 24. A neuromodulation catheter, comprising: an elongate shaft including two or more cut shapes configured to at least partially resist deformation in response to compression on the shaft along a longitudinal axis of the shaft, tension on the shaft along the longitudinal axis, torsion on the shaft in a first circumferential direction perpendicular to the longitudinal axis, and torsion on the shaft in a second circumferential direction opposite to the first circumferential direction, the cut shapes being distributed along a helical path extending about the longitudinal axis; and a neuromodulation element operably connected to the shaft via a distal end portion of the shaft.
 25. The neuromodulation catheter of claim 24 wherein the shaft includes tabs adjacent to the cut shapes, the individual tabs including a flared portion and a restricted portion.
 26. The neuromodulation catheter of claim 25 wherein: the flared portion includes a rounded head; and the restricted portion includes a rounded neck.
 27. The neuromodulation catheter of claim 25 wherein: the flared portion comprises a wedge-shaped head; and the restricted portion comprises a rounded neck, and wherein the individual tabs and corresponding cut shapes comprise interlocking, wedge-shaped components.
 28. A neuromodulation catheter, comprising: an elongate shaft including two or more sinusoidal cut shapes; and a neuromodulation element operably connected to the shaft via a distal end portion of the shaft, wherein— the cut shapes are distributed along a helical path extending around a longitudinal axis of the shaft; and the cut shapes have an orientation that is perpendicular to the helical path.
 29. The neuromodulation catheter of claim 28 wherein: the individual cut shapes include a first peak and a second peak with an interface therebetween; and the interface is perpendicular to the helical path.
 30. A neuromodulation catheter, comprising: an elongate shaft including— a first helically wound elongate member having a series of first windings with a first average helix angle, the first windings at least partially forming a first tubular structure; and a second helically wound elongate member having a series of second windings with a second average helix angle, the second windings at least partially forming a second tubular structure; and a neuromodulation element operably connected to the shaft via a distal end portion of the shaft, wherein— the first tubular structure is disposed within the second tubular structure, the first and second tubular structures are concentric, and the first average helix angle is different than the second average helix angle by an angle within a range from about 10 degrees to about 140 degrees.
 31. The neuromodulation catheter of claim 30 wherein a difference between the first and second average helix angles changes at least once along a length of the shaft.
 32. The neuromodulation catheter of claim 30 wherein a difference between the first and second average helix angles decreases distally along the length of the shaft.
 33. The neuromodulation catheter of claim 30 wherein the shaft includes a biocompatible jacket at least partially encasing the first and second tubular structures.
 34. The neuromodulation catheter of claim 30 wherein: the first tubular structure includes a transition region; and the first windings on either side of the transition region having different average helix angles.
 35. The neuromodulation catheter of claim 30 wherein: the second tubular structure includes a transition region; and the second windings on either side of the transition region have different average helix angles.
 36. The neuromodulation catheter of claim 30 wherein at least one of the first and second helically wound elongate members is multifilar.
 37. The neuromodulation catheter of claim 30 wherein the first and second helically wound elongate members are multifilar.
 38. The neuromodulation catheter of claim 30 wherein an axial density of the first windings, the second windings, or both along a longitudinal axis of the shaft is selected to facilitate intravascular delivery of the neuromodulation element to a treatment location within or otherwise proximate to a renal artery of a human patient via a transradial approach.
 39. The neuromodulation catheter of claim 30 wherein: the first and second tubular structures extend along a portion of a longitudinal axis of the shaft, the portion of the longitudinal axis corresponding to a segment of the shaft; and a distance along the longitudinal axis between the neuromodulation element and the segment is selected to cause the segment to be at least proximate to a relatively sharply angled or otherwise relatively tortuous region of a transradial approach when the neuromodulation element is operably positioned at a treatment location within or otherwise proximate to a renal artery of a human patient.
 40. The neuromodulation catheter of claim 39 wherein the relatively sharply angled or otherwise relatively tortuous region is within or otherwise proximate to a subclavian artery.
 41. A neuromodulation catheter, comprising: an elongate shaft including— a first segment made at least partially of a first shape-memory alloy having a first shape-memory transformation temperature range, and a second segment made at least partially of a second shape-memory alloy having a second shape-memory transformation temperature range lower than the first shape-memory transformation temperature range, the second segment being proximal to the first segment along a longitudinal axis of the shaft; and a neuromodulation element operably connected to the shaft via a distal end portion of the shaft.
 42. The neuromodulation catheter of claim 41 wherein: the elongate shaft includes a third segment made at least partially of a third shape-memory alloy, the third segment being between the first and second segments along the longitudinal axis; the first, second, and third shape-memory alloys are the same; and a shape-memory transformation temperature range of the third shape-memory alloy gradually increases along the third segment from the second segment toward the first segment.
 43. The neuromodulation catheter of claim 42 wherein the first, second, and third shape-memory alloys are nitinol.
 44. The neuromodulation catheter of claim 43 wherein: the first shape-memory transformation temperature range includes an Af temperature greater than body temperature; and the second shape-memory transformation temperature range includes an Af temperature less than body temperature. 